What is Age-Related Macular Degeneration?
Age-related macular degeneration (AMD) is one of the leading causes of vision impairment among older adults in the United States. It leads to vision loss typically in the center of one’s vision, making it difficult to recognize faces or to read books or newspapers. Advances in the diagnosis and treatment of AMD over the past decade have improved the chances of preserving or even regaining vision and maintaining independence in daily living activities.
How does macular degeneration damage the eye?
Age-related macular degeneration is caused by the formation of abnormal deposits called drusen or abnormally fine blood vessels that leak fluid or blood underneath a part of the eye called the retina.
If you think of the eye like a camera, the retina is like the film in a camera. It contains the photoreceptors that detect light and send the images to your brain to allow you to see.
With age-related macular degeneration, the retina becomes bumpy and distorted. So, the images detected by a retina that has an irregular surface will cause images to become distorted once they get to the brain. It is similar to how pictures might look when they become warped by exposure to heat.
Eventually, these areas in the retina where fluid or blood have leaked may eventually form scar tissue. As a result, blind spots may form in the center of the vision.
What increases the risk for age-related macular degeneration?
There are several factors that contribute to an increased risk for age-related macular degeneration. Those include:
- Older age
- White race
- Family history of macular degeneration
- Tobacco use
- High blood pressure or high cholesterol
How is age-related macular degeneration diagnosed?
Age-related macular degeneration can be diagnosed during a complete eye examination by an ophthalmologist -- a medical doctor specializing in medicine and surgery for the eyes.
There are several tests that your ophthalmologist may perform:
- Visual acuity testing: Your ability to read the letters on an eye chart may be affected by AMD, especially since it tends to affect the center of one’s vision.
- Amsler grid testing: An Amsler grid looks like graph paper, or a grid of crisscrossed lines. The lines should look straight and cross at right angles. But if the surface of the retina is distorted by AMD, it will cause corresponding areas of the Amsler grid to look wavy or blurred. This is a test that patients can do at home to regularly monitor their vision.
- Dilated retinal exam: Your ophthalmologist will use special eye drops that will dilate your pupils to examine the retina, the part of the eye damaged by age-related macular degeneration. In early stages of AMD, your doctor may see drusen, which are yellow spots containing fat that form underneath your retina. In more advanced stages, fluid or blood may be seen leaking into the retina.
- Retinal imaging: Your doctor may take various pictures of your retina to help diagnose and manage macular degeneration. Optical coherence tomography, or OCT for short, has helped to revolutionize the management of AMD in the past 10 years. OCT is a way of taking a picture of the different layers of the retina using light rays. It helps your doctor see where fluid leaking may be leaking into the retina and determine the most appropriate treatment.
- Fluorescein angiography: This procedure involves taking pictures of the retina as a yellow dye flows through the blood vessels. It is another way to help your doctor evaluate the health of the retina.
How is age-related macular degeneration treated?
If you have early age-related macular degeneration, you may be advised to take a daily multivitamin and to monitor your vision with an Amsler grid. Early on, it is important to be aware of the symptoms of fluid leakage into the retina, at which point more aggressive treatment is needed.
If macular generation becomes “wet,” that means fluid or blood has collected underneath the retina. Medications can be administered through an injection into the eye to shrink abnormal leaky blood vessels. Consistent follow-up with the eye doctor is very important at this stage, because medication may need to be administered to the eye as often as every month.
Thanks to these injectable medicines that became available in the 2000s, many patients have been able to maintain or improve their vision. Some patients with wet macular degeneration benefit from laser treatment to prevent further vision loss. Special eye vitamins known as “AREDS2” are also recommended for patients with this form of macular degeneration to reduce its chance of progression.
In later stages of the disease, scarring may develop in the center of the retina. This leads to blind spots in the central vision. Special low vision aids can help improve the ability to read books and other print materials. There is research underway to help find better treatments for patients with advanced AMD.
What can I do to prevent or manage age-related macular degeneration?
- Have your eyes checked on a regular basis by an ophthalmologist, especially if you have any of the risk factors above.
- Avoid tobacco products. Smoking has been shown to increase risk of developing age-related macular degeneration.
- Include foods rich in lutein such as kale, spinach and other colorful fresh fruits and vegetables in your diet.
- Monitor your vision in each eye with an Amsler grid periodically. See your eye doctor if you notice any changes in your vision.
About the Author:
Lifespan Physician Group Ophthalmology
Lifespan Physician Group Ophthalmology provides a full spectrum of ophthalmology services, from diagnosis and treatment of common eye diseases to cataract surgery, ophthalmic plastic and reconstructive surgery. Our ophthalmology team sees referrals from within the Lifespan system as well as patients from the community.
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